lavfi/framesync: reword repeatlast option help.

doc/filters.texi

@@ -337,9 +337,9 @@ If set to 1, force the output to terminate when the shortest input
 terminates. Default value is 0.
 
 @item repeatlast
-If set to 1, force the filter to draw the last overlay frame over the
-main input until the end of the stream. A value of 0 disables this
-behavior. Default value is 1.
+If set to 1, force the filter to extend the last frame of secondary streams
+until the end of the primary stream. A value of 0 disables this behavior.
+Default value is 1.
 @end table
 
 @c man end OPTIONS FOR FILTERS WITH SEVERAL INPUTS

libavfilter/framesync.c

@@ -41,7 +41,7 @@ static const AVOption framesync_options[] = {
         { "endall", "End both streams.",            0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_ENDALL }, .flags = FLAGS, "eof_action" },
         { "pass",   "Pass through the main input.", 0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_PASS },   .flags = FLAGS, "eof_action" },
     { "shortest", "force termination when the shortest input terminates", OFFSET(opt_shortest), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
-    { "repeatlast", "repeat overlay of the last overlay frame", OFFSET(opt_repeatlast), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, FLAGS },
+    { "repeatlast", "extend last frame of secondary streams beyond EOF", OFFSET(opt_repeatlast), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, FLAGS },
     { NULL }
 };
 static const AVClass framesync_class = {